Answer:The isotope is Carbon-12 and its atomic mass is 12.
Explanation:
Mass number is the total number of protons and neutrons in a nucleus.
Atomic number is the number of protons in the nucleus of an atom.
An isotope of a chemical element is an atom that has a different mass number but the same atomic number as the element. The difference in mass number is from the number of neutrons (that is, a greater or lesser atomic mass) than the standard for that element.
Carbon-12 is an isotope of carbon it has 6 neutrons and 6 protons, giving it a mass number of 12 and atomic number of 6. Carbon-12 is a stable isotope of carbon, it has the same mass number and atomic number as carbon.
